Genetic illness can be stopped

The research could change the lives of millions fated to suffer from deadly or debilitating conditions passed down through generations.

Scientists believe that if their research is developed as they hope, it will pave the way for disease-free, designer babies to be born without inherited disorders, including some heart problems. Researchers think the revolutionary IVF technique could stop the process of a mother transmitting cell defects to her child.

It has already been tried out on Rhesus monkeys, resulting in the birth of four healthy babies.

The researchers, who reported their findings online in the journal Nature, say there is no reason why the same principle should not be a success in humans.

It raises the prospect of banishing disease caused by defective genes in mitochondria – tiny sausage-shaped “batteries” inside cells which turn the food we eat into energy. This is then used by the heart, muscles, brain and other body parts.

Scientists believe it will only be a few years before they are ready to test the technique on human patients, assuming they get the funding and ethical go-ahead.

This kind of research is currently banned in the UK, but the new Human Fertilisation and

Embryology Act, which becomes law on October 1, could open the door to similar trials with the approval of Parliament.

Dr Duane Alexander, director of the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Maryland, US, said: “The findings hold the potential of allowing a couple to have a child who is biologically theirs, but is free of any conditions associated with defects in maternal mitochondria.”

The technique swapped the hereditary material in one female’s egg with that from another.

The resultant eggs – fertilised with donor sperm and implanted in females and carried to term – produced offspring possessing mitochondria from the “healthy” donated egg cell.

It is defects in the DNA of mitochondria that affect more than one in 5,000 babies and causes around 50 genetic diseases, many of which result in disabilities and can kill before adulthood.

These defects have been linked to a variety of conditions including diabetes, some cancers and infertility along with neuro- degenerative disorders like Alzheimer’s, Parkinson’s and Huntington’s diseases.

They also include muscle- wasting mitochondrial myopathies, Leber’s Hereditary Optic Neuropathy which leads to blindness, nerve illnesses similar to multiple sclerosis and conditions that damage organs.

This technique raises the possibility mitochondria associated with a hereditary disorder could be prevented from being passed on to the next generation.

But critics are likely to condemn the findings claiming they could lead to genetically- modified babies being “designed to order”, with parents choosing sex and eye colour as well as getting rid of genetic faults.

Mitochondria is passed on to subsequent generations only through egg cells and not transmitted through sperm. Using the new method, researchers at Oregon Health Science University created fertilised eggs and achieved three successful pregnancies in Rhesus monkeys which resulted in four healthy babies.

Professor Peter Braude, director of the Centre for Preimplantation Genetic Diagnosis at Guy’s Hospital, London, said: “This is a meticulously executed series of technically difficult experiments.

“For the first time, proof of principle has been demonstrated that transmission of mitochondrial disease might be avoided.”

Alastair Kent, director of Genetic Interest Group, the UK alliance organisation for all people affected by genetic conditions, said: “We welcome this exciting development, but recognise that there is still a long way to go before this becomes available as a safe and effective therapy.”

A spokesman for the Human Fertilisation and Embryology Authority, said: “The HFEA has licensed a number of research projects into mitochondrial diseases, but with very tight restrictions on the research methods.”